Improvement in the manufacture of tension-wheels for sewing-machines



for Sewing-Machines.

Patented June18, I872.

AM. FHGM-HTHOGRMWIO m, MK (omen/1:3 PROCESS,

UNITED STATES IRA MANNING, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN THE MANUFACTURE OF TENSION-WHEELS FOR SEWING-MACHINES.

Specification forming part of Letters Patent No. 128,051, dated June 18,1872.

Specification describing certain Improvements in the Tension-Wheel of aSewingMachine, invented by IRA MANNING, of the city and county ofPhiladelphia and State of Penn'- sylvania.

The improvements relate to casting or otherwise making the tension wheelof a sewingmachine in one piece, and afterward pressing or forcing thesame for the purpose of finishing the thread-groove.

Figures 1 and 2 are enlarged sectional views. Fig. 3 is an enlarged sideview.

The wheel A is formed or cast in a single piece; A V-shapcd groove iscut in its rim, and afterward placed in a press or other suitablemachine and pressed or forced until the angle 0 of the V becomesextremely fine and knife-edge like, as shown at Fig. 2. Heretofore ithas not been possible to cut a V-groove in a solid tension-wheel, and atthe same time make its angle 0 sufficiently sharp to pinch the thread,and thereby cause the necessary tension. Cutting-tools might be madewith points of sufiicient fineness and durability to cut a groove forthe coarser grades of thread,

but for fine silk or cotton it is practically impossible. Afterthegroove has been completed it can be freed of dirt or deposit by openingsd, Fig. 3, the peripheries of whichcut or break, at intervals, the anglec.- The angle or bottom of the V-shaped groove b is shown by the line 0;the peripheries of the openings (1 project slightly above it. Thesliding of the thread carries all deposit into these openings and keepsthe groove free of dirt.

I claim as my invention The improved method, herein described, of makingtension-wheels for sewing-maohines that is to say, casting or otherwiseconstructing the wheel of one piece of metal, then form

